The present invention relates to a method and composition for prolonging the usable life of fibrous materials. In more detail, the present invention relates to a composition for use as a preservative for such materials as ropes and fishing nets, including a urethane resin, a solvent, a drying agent, and, optionally, a coloring agent, antioxidant or antiskinning agent. Further, the present invention relates to a process for treating such fibrous materials to prolong their useful life which comprises applying the preservative to the fibrous material and subsequently drying the fibrous material.
Most fishing nets are made of various filamentous vegetable fibers, including cotton, linen, jute, or flax. Others are constructed from continuous synthetic resin fibers such as nylon, orlon, dacron, polyethylene, or polypropylene.
Numerous methods have been employed to prolong the usable life of fishing nets, including dipping the nets in paraffin or tar-based coatings, synthetic resins, a composition commonly known as "green dip", or a latex compound. U.S. Pat. No. 4,457,959 discloses a latex coating for fishing net, which is intended to minimize crimping and shrinking of nets. Those coating processes help to lock the knots of the net and decrease fraying of the filamentous strands forming the net. Locking the knots is desirable to prevent the deformation of the net when a heavy load is placed upon it. However, those coatings are limited in their ability to protect the fishing net to which they are applied from the elements to which those nets are exposed, including water and sunlight, because they either do not penetrate between the fibers of the fibrous material comprising the net, or penetrate minimally, and because they do not block the ultraviolet rays of the sun. So far as is known, no treatment exists to protect fishing nets from ultraviolet light, an important consideration due to the fact that fishing nets are alternately immersed in water and then dried in the sun. When the water is salt water, and when the net is comprised of a synthetic fiber, exposure to the sun is particularly damaging. Further, present methods afford protection to a net for a relatively limited period of time, and therefore, the treatment must be repeated at intervals as often as once a month during the useful life of a net.
Fishing nets have also been treated with chemical coatings intended to prevent the adhesion of algae and/or shell fish to the nets. For instance, U.S. Pat. No. 4,297,803 discloses the use of a coating of triisobutyltin hydroxide and an arylsulphonic acid derivative dissolved in an organic solvent to prevent the adhesion of algae and/or shellfish. However, this coating is of little or no use as a treatment for preserving the integrity of the nets because, so far as is known, it does not lock the knots and penetrates only minimally between the fibers. Nor is it effective at blocking even a portion of the sun's rays.
Another treatment which is directed to the same object, that of preventing or postponing deterioration of the net due to environmental factors, is disclosed in U.S. Pat. No. 2,590,586. That patent discloses a synthetic resin filament net, coated with either an ester-type resin derived from ethylene glycol and terephthalic acid, and maleic and aklyd resins, or a vinyl resin such as polyvinyl chloride, nylon polystyrene or acrylic resins such as polymethacrylate, melamine-formaldehyde resin, furan resin, or copolymers of those resins. The stated purposes of the net coating disclosed in that patent are to promote knot retention and to suppress the plastic "memory" of the resin core.
The netting formed according to that patent is believed to have certain disadvantages and limitations. For example, the preservative is applied to filaments formed from a synthetic resin, and the treatment process, involving heating, stretching, and drying, is performed prior to manufacture into a net. The net formed of the synthetic resin strands, and the method of producing the net, uses only polyester resins, and production of the net is resultantly complex and expensive. Further, so far as is known, the netting which results from the process disclosed in that patent is still vulnerable to sunlight.
There is, therefore, a need for a method or composition capable of extending the useful life of fibrous materials, in particular, fishing nets, which is capable of preventing deterioration of the net due to penetration of water between the net fibers, slipping of the knots of the net, and damage from exposure to the sun. Ideally, such a method should be one which may be performed only once or a very few times during the life of a net.
It is, therefore, an object of the present invention to provide a simpler method of treatment of any manufacture or composition of net, and a preservative of unique composition for such treatment, which is capable of prolonging the useful life of a fishing net or other fibrous material.
It is another object of the present invention to provide a composition and method which overcomes the problem of deterioration of nets and other fibrous materials due to alternating exposure to water and sunlight by rendering the net or fibrous material treated with that composition almost impervious to water absorption and exposure to sunlight.
It is another object of the present invention to provide a fishing net constructed of twisted nylon trifilament and treated with a preservative formulated according to the present invention which retains its knot integrity, knot spacing, and net rigidity without excessive bulk to such an extent that the life of a net in actual use is prolonged over that of any other treated or non-treated net.
Another object of the present invention is to provide a highly durable fishing net.
A further object of the present invention is to provide a composition for treating nets in general, such that a net so treated is strong, sun and water-resistant for a long period of time.
It is another object of the present invention to provide a new and useful fishing net in which the treatment modality is simple and need be performed only once prior to use of the net.
It is another object of the present invention to provide a method and composition useful for treatment of nets and rope materials such as nets and ropes for tennis courts, batting cages, hockey goal nets, animal trapping, flag poles and so on which increases the durability and weather resistance of those materials.
It is another object of the present invention to provide a method of preservating fibrous material comprising mixing a urethane resin with a thinning agent, contacting the fibrous material with that mixture, and thereafter, drying the fibrous material.
Other objects, features, and advantages of the invention, will become evident to those skilled in the art from the following detailed description.